net/dsa/tag_qca.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2015, The Linux Foundation. All rights reserved.
   4  */
   5
   6 #include <linux/etherdevice.h>
   7
   8 #include "dsa_priv.h"
   9
  10 #define QCA_HDR_LEN     2
  11 #define QCA_HDR_VERSION 0x2
  12
  13 #define QCA_HDR_RECV_VERSION_MASK       GENMASK(15, 14)
  14 #define QCA_HDR_RECV_VERSION_S          14
  15 #define QCA_HDR_RECV_PRIORITY_MASK      GENMASK(13, 11)
  16 #define QCA_HDR_RECV_PRIORITY_S         11
  17 #define QCA_HDR_RECV_TYPE_MASK          GENMASK(10, 6)
  18 #define QCA_HDR_RECV_TYPE_S             6
  19 #define QCA_HDR_RECV_FRAME_IS_TAGGED    BIT(3)
  20 #define QCA_HDR_RECV_SOURCE_PORT_MASK   GENMASK(2, 0)
  21
  22 #define QCA_HDR_XMIT_VERSION_MASK       GENMASK(15, 14)
  23 #define QCA_HDR_XMIT_VERSION_S          14
  24 #define QCA_HDR_XMIT_PRIORITY_MASK      GENMASK(13, 11)
  25 #define QCA_HDR_XMIT_PRIORITY_S         11
  26 #define QCA_HDR_XMIT_CONTROL_MASK       GENMASK(10, 8)
  27 #define QCA_HDR_XMIT_CONTROL_S          8
  28 #define QCA_HDR_XMIT_FROM_CPU           BIT(7)
  29 #define QCA_HDR_XMIT_DP_BIT_MASK        GENMASK(6, 0)
  30
  31 static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
  32 {
  33         struct dsa_port *dp = dsa_slave_to_port(dev);
  34         u16 *phdr, hdr;
  35
  36         if (skb_cow_head(skb, QCA_HDR_LEN) < 0)
  37                 return NULL;
  38
  39         skb_push(skb, QCA_HDR_LEN);
  40
  41         memmove(skb->data, skb->data + QCA_HDR_LEN, 2 * ETH_ALEN);
  42         phdr = (u16 *)(skb->data + 2 * ETH_ALEN);
  43
  44         /* Set the version field, and set destination port information */
  45         hdr = QCA_HDR_VERSION << QCA_HDR_XMIT_VERSION_S |
  46                 QCA_HDR_XMIT_FROM_CPU | BIT(dp->index);
  47
  48         *phdr = htons(hdr);
  49
  50         return skb;
  51 }
  52
  53 static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev,
  54                                    struct packet_type *pt)
  55 {
  56         u8 ver;
  57         int port;
  58         __be16 *phdr, hdr;
  59
  60         if (unlikely(!pskb_may_pull(skb, QCA_HDR_LEN)))
  61                 return NULL;
  62
  63         /* The QCA header is added by the switch between src addr and Ethertype
  64          * At this point, skb->data points to ethertype so header should be
  65          * right before
  66          */
  67         phdr = (__be16 *)(skb->data - 2);
  68         hdr = ntohs(*phdr);
  69
  70         /* Make sure the version is correct */
  71         ver = (hdr & QCA_HDR_RECV_VERSION_MASK) >> QCA_HDR_RECV_VERSION_S;
  72         if (unlikely(ver != QCA_HDR_VERSION))
  73                 return NULL;
  74
  75         /* Remove QCA tag and recalculate checksum */
  76         skb_pull_rcsum(skb, QCA_HDR_LEN);
  77         memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - QCA_HDR_LEN,
  78                 ETH_HLEN - QCA_HDR_LEN);
  79
  80         /* Get source port information */
  81         port = (hdr & QCA_HDR_RECV_SOURCE_PORT_MASK);
  82
  83         skb->dev = dsa_master_find_slave(dev, 0, port);
  84         if (!skb->dev)
  85                 return NULL;
  86
  87         return skb;
  88 }
  89
  90 static int qca_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
  91                                 int *offset)
  92 {
  93         *offset = QCA_HDR_LEN;
  94         *proto = ((__be16 *)skb->data)[0];
  95
  96         return 0;
  97 }
  98
  99 static const struct dsa_device_ops qca_netdev_ops = {
 100         .name   = "qca",
 101         .proto  = DSA_TAG_PROTO_QCA,
 102         .xmit   = qca_tag_xmit,
 103         .rcv    = qca_tag_rcv,
 104         .flow_dissect = qca_tag_flow_dissect,
 105         .overhead = QCA_HDR_LEN,
 106 };
 107
 108 MODULE_LICENSE("GPL");
 109 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_QCA);
 110
 111 module_dsa_tag_driver(qca_netdev_ops);